title: Effects of velocity of isokinetic training on strength, power, and quadriceps muscle fibre characteristics.
abstract: Twenty young men trained the right knee extensors and flexors on an isokinetic dynamometer three times weekly over a 10-week period. During each session, 10 men in the slow training group completed three sets of 8 maximal contractions at a rate of 1.05 rad s-1, whereas the other 10, the fast group, completed three sets of 20 contractions at a rate of 4.19 rad s-1. Subjects wer pre- and post-tested for peak torque and power on an isokinetic dynamometer at 1.05, 3.14, and 4.19 rad s-1. Proportions of muscle fibre-types and fibre cross-sectional areas were determined from biopsy specimens taken before and after training from the right vastus lateralis. When testing was conducted at 1.05 rad s-1, the slow group improved (P less than 0.05) peak torque by 24.5 N m (8.5%), but no change was noted for the fast group. Power increased (P less than 0.05) by 32.7 W (13.6%) in the slow group and 5.5 W (2.5%) in the fast. At 3.14 rad s-1, both groups increased (P less than 0.05) peak torque and power. At 4.19 rad s-1, the fast group increased (P less than 0.05) peak torque by 30.0 N m (19.7%), whereas no training effect was observed in the slow group. There was no significant change in power in either group at 4.19 rad s-1. No significant changes were observed over the 10-week training period in percentages of type I, IIa and IIb fibres, but both groups showed significant increases (P less than 0.05) in type I and IIa fibre areas.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Exercise Physiology Research Laboratory, Michigan State University.
authors.forename: J L
authors.initials: JL
authors.lastname: Ewing
authors.forename: D R
authors.initials: DR
authors.lastname: Wolfe
authors.forename: M A
authors.initials: MA
authors.lastname: Rogers
authors.forename: M L
authors.initials: ML
authors.lastname: Amundson
authors.forename: G A
authors.initials: GA
authors.lastname: Stull
mesh_terms: D000328:Adult; D015444:Exercise / Q000502:physiology*; D006651:Histocytochemistry; D006801:Humans; D007866:Leg / Q000033:anatomy & histology; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D009132:Muscles / Q000033:anatomy & histology / Q000166:cytology / Q000502:physiology*; D009929:Organ Size / Q000502:physiology; D010806:Physical Education and Training